(high end graphics cards hog a lot of system bandwidth)
Oh dear God.... Not only are you completely wrong, this statement does not even stand up to simple logic...
The whole point of higher end vid systems is to lower system utilization by off loading the graphics tasks from CPU and PCI bus...
And I am not talking about 3D, I am talking about 2D. Somehow the graphics still need to be drawn on the screen, and it becomes increasingly important when resolutions climb, such as with todays modern hi-res large monitors or worse yet, dual monitors. Higher end vid systems have faster and higher bit rate memory controllers and better scheduling.
Low end vid systems on the other hand put the CPU into wait states... they decrease system performances because they are so slow, and because they tend to use cheap technologies that rely on the system for things like memory access and so on (some even are simply AGP cards with a PCIe bridge chip which is even worse for system performance, as its yet another layer of processing)
And FYI, the 6600 was
a high end vid card a couple of years ago. It performed nearly as well as as the (then) top of the line 6800. I owned two of them they were so good. The reason its cheap now is not because its low end, but because its obsolete. We are now at the 9xxx level.
To the OP. Sorry for hijacking your thread, but this BS needs to be stamped out once and for all.
As for a system that optimized for PS, do not worry about it. If it runs smoothly then it should work fine. I also do graphics (and vid NLE, and application development and networking and play games and watch DVDs and, well, everything) work on my DAW, and it is flawless in all tasks. The only problems I experience are those that are well known like the sudden 100db sound increase, which has zero to do with the vid card, and is actually a bug in Cakewalk. And yes, I have a high end vid card...